Scanning exposure method, scanning exposure apparatus and making method for producing the same, and device and method for manufacturing the same

ABSTRACT

A main control system determines a mode of a focusing control based on both data representing the surface condition of a divided area and data for a shape of an illumination area on a wafer. Then, the main control system controls actuators based on detection results from a focus sensor, and performs the focusing control of a substrate stage for holding the wafer in respect to a projection optical system. Simultaneously with the focusing control, the main control system controls a wafer stage driving block to control the synchronous movement of a reticle stage and substrate table. Thereby a pattern formed on a reticle is transferred onto the divided area on the wafer via the projection optical system. Not premising a high focusing control driving practicability, the pattern is transferred onto the substrate without serious deterioration of imaging performance.

TECHNICAL FIELD

The present invention relates to a scanning exposure method, a scanningexposure apparatus and making method thereof, and a device and a devicemanufacturing method. More particularly, the present invention relatesto a scanning exposure method to be employed in a lithographic processfor manufacturing a semiconductor device, a liquid crystal displaydevice and so forth; a scanning exposure apparatus on which the scanningexposure method is applied and a making method thereof; as well as adevice which is manufactured by using the scanning exposure apparatusand a manufacturing method thereof.

BACKGROUND ART

Conventionally, in a lithographic process for manufacturing asemiconductor device, liquid crystal display device and so forth, anexposure apparatus has been used. In such an exposure apparatus,patterns formed on a mask or reticle (to be genetically referred to as a“reticle” hereinafter) are transferred through a projection opticalsystem onto a substrate such as a wafer or glass plate (to be referredto as a “substrate or wafer” herein after, as needed) coated with aresist or the like. In general, a projection optical system with a largenumerical aperture (to be referred to as “N.A.”, hereinafter) and ashallow focal depth is used in the projection exposure apparatus. Themechanism to bring the substrate surface to a proximate level of animaging plane in the projection optical system is necessary for theprojection exposure apparatus for transferring fine circuit patternsonto a substrate with high resolution. Therefore, the exposure apparatushas a focusing system for brining the substrate surface to the range ofthe focal depth of the projection optical system. The system is composedof the focus/leveling detecting mechanism and the adjusting mechanism,and the system is referred to as the “Z-leveling stage” herein after.The focus/leveling detecting mechanism detects the position and tilt ofthe substrate surface in optical axis direction of the projectionoptical system (that is, Z-direction), and the adjusting mechanismadjusts the position and the posture of the substrate surface by usingthe detected position and the tilt of the surface in Z-direction.

On the contrary, semiconductor chip devices recently tend to belarge-sized, and there is needs to transfer larger patterns onto thesubstrate by the projection exposure. For satisfying such needs,so-called step and scan type scanning exposure apparatus is practicallyused. In the apparatus, a reticle and the substrate are synchronouslyscanned against the projection optical system, shot areas are exposedover the effective illumination area of the projection optical system.In the scanning type exposure apparatus, in order to expose a shot areaon the substrate surface, the shot area, i.e. substrate, and the reticlemust be moved synchronously with the fixed velocity commensurate to thepredetermined exposure dose amount, while the substrate and the reticleare positioning. Therefore, the following procedures are included: thestage on which the substrate is loaded (XY stage) is allowed to run whenthe shot area is far from exposure area on the substrate surface, onwhich exposure light is illuminated when the light is passed through theprojection optical system; the stage loading the substrate and the stageloading the reticle are synchronized; and then, the exposure is begun atthe time that the shot area on the substrate is reached the exposurearea.

As a part of the procedure, the positional information in Z-directionand the tilt information in the synchronized moving direction and theunsynchronized moving direction (i.e., perpendicular to the synchronizeddirection) are detected for the substrate surface area in the exposurearea. By using this detection result, the focusing operation isperformed for the substrate surface area in the exposure area. In thefocusing operation, the focusing operation for focusing in the opticalaxis direction of the projection optical system (Z-direction) and theleveling operation for focusing in tilt direction around X-axis andY-axis are simultaneously performed. Thereby, the difference between theexpose plane on the substrate and the image plane of the projectionoptical system becomes minimal. When the synchronous moving direction isY-direction, the tilt for the synchronous moving direction isrepresented as the rotational amount around X-axis, and that in theasynchronous moving direction is represented as the rotational amountaround Y-axis.

In the step and scan type scanning exposure apparatus, since thesubstrate to be exposed is moved during the exposure, the control isrepeated successively so that the image plane of the projection opticalsystem closes to the exposure plane on the surface of the photosensitivesubstrate. Accordingly, in the typical structure of the Z-leveling stagein which the driving mechanism is arranged periphery of the substrate,most of the driving load in the leveling stage is caused by the levelingoperation.

In such scanning exposure apparatuses, the slit shape of the exposurearea on which the exposure light passed through the projection opticalsystem is generally In the shape of the exposure area, the length in thesynchronous moving direction (for example, Y-direction) is shorter thanthat in the asynchronous moving direction (for example, X-direction).Based on the shape of the exposure area, focus detection points arearranged inside of the exposure area (and outside of it, if necessary).At that time, the length that is used as the base line for calculatingthe tilt components in the synchronous moving direction is shorter thanthat in asynchronous direction. Therefore, the leveling action for theasynchronous direction greatly contributes to the driving load on theZ-leveling stage.

That is, in the step and scan type scanning apparatus, most of thedriving practicability of the Z-leveling stage is spent to the levelingaction in the scanning direction.

Integrated circuit patterns formed on the substrate often have differentnumber of starts, and it causes the increase of driving load for theZ-leveling stage in the leveling action for the synchronous movingdirection. In the substrate having such different number of stairs, thestair pattern formed by the different number of stairs sometimes has theperiodical repeating components. Furthermore, the distribution state ofthe period varies depending on, for example, the application orcharacteristics of the integrated circuit pattern. When the ratio of theshort periodical components is high, the driving load for the levelingaction in the synchronous moving direction. Therefore, the drivingpracticability of Z-leveling stage should be high must, and it causesthe structure of Z-leveling stage to be complicate and large scaled.

When the performance of z-leveling stage does not fulfill the requiredperformance for following-up the leveling in the synchronous direction,the adjustment of the leveling is insufficient. Furthermore, when 100%of the performance of Z-leveling stage is applied for following-up theleveling caused by the difference number of the stairs in thesynchronous moving direction, it is impossible to correct the figure ofthe substrate except the difference (for example, warpage or swell inthe raw substrate). Thereby nonlinear area is generated which causes toloose control, and the transfer of the pattern can be affected by moreserious effect such as awful deterioration for imaging and so forth.

The present invention has been made in consideration of theabove-mentioned situation. The first object of the present is to providethe exposure method for transferring a pattern without extremedeterioration of the imaging performance.

The second object of the present invention is to provide the exposureapparatus for transferring a pattern without extreme deterioration ofthe imaging performance.

The third object of the present invention is to provide the device onwhich fine patterns are precisely formed.

DISCLOSURE OF INVENTION

As mentioned above, in the scanning exposure by the so-called step andscan member, high focusing driving power is necessary as the premise foraccurate focusing control at respective time point during exposure byfollowed-up the synchronous moving. According to the knowledge from thestudy conducted by the present inventors, the exposure area to beilluminated by the exponent light generally has a certain slit with inthe synchronous moving direction. Therefore, when the period of theconvex and concave in the divided area on the substrate surface havingthe difference of a stair is shorter than the slit width, the imagingperformance is not improved by amending the leveling in the synchronousmoving direction to follow-up the difference of the stair.

That is, when the repeating period of the difference on the substrate isshorter than the slit width, the defocus amount in the part around thecenter is run into almost 0 by the follow-up of the leveling in thesynchronous moving direction. However, around of the edge of theexposure area is exposed under the condition that rather large defocusamount resides (see FIG. 9A). In this case, as shown in Japan laid-openNo. S63-64037 and its corresponding U.S. Pat. No. 4,869,999, thesuperimposed focal exposure, in which the decline of the focal depth isamended by the superimposing projected images at different focuspositions, is performed. In the superimposed focal exposure, theexposure is performed with three conditions of the positive defocusamount/no defocus amount/negative defocus amount. On the contrary, whenthe follow-up of the leveling in the synchronous moving direction is notused, the defocus amount in the part around the center of the exposurearea is almost 0. Except the part around the center of the exposure areais exposed under the condition in which the defocus amount in proportionto the distance from the center remains (see, FIG. 9B). In this case, asshown in Japan laid-open No. H5-13305 and its corresponding U.S. Pat.No. 5,343,270, the continuous superimposed exposure from the positivedefocus amount to the negative one is performed.

Since various parameters such as the photoresist agents and so forth arerelated, it is case by case that either one give results that are mostdesirable in brief. However, when the leveling is followed-up,Z-leveling stage is applied more load. Therefore, on the design of theapparatus, Z-leveling stage must be designed to have larger margin inits performance. Being estimated shorter the period of the difference ofthe stair in the substrate, being clearer the tendency.

The present invention is completed based on the above description. Inthe first aspect of the present invention, the present invention is thescanning exposure method for transferring a pattern formed on a mask toa divided area on a substrate through a projection optical system, whilesaid mask and said substrate are synchronously moved, comprising thesteps of: deciding a focusing control mode to be used when said patternis transferred onto the divided area in a plurality of focusing controlmodes, depending on a surface condition of the divided area;transferring the pattern formed on the mask onto the divided area andperforming said focusing control in the decided mode.

With this, the mode of the focusing control is decided, depending on thesurface condition of the divided area. Then, the pattern formed on themask is transferred onto the divided area, performing the focusingcontrol with the properly adjusted mode Accordingly, the properlyadjusted focusing control action might be performed, depending on thesurface condition of the divided area in which the warpage or swell ofthe raw substrate is reflected. Therefore, the pattern formed on themask is transferred onto the substrate with no serious deterioration ofthe imaging performance or no premise for the high drivingpracticability for the focusing control (to be referred to as the“focusing control driving power”).

The focusing control might include the focus position control thatcontrols the position of the substrate in the optical axis direction ofthe projection optical system. In addition, it might include theleveling control that controls the tilt of the substrate to the planeperpendicular to the optical axis direction of the projection opticalsystem. The leveling control might include the tilt control of thesubstrate in the synchronous moving direction and the tilt control ofthe substrate in the direction perpendicular to the synchronous movingdirection in the plane perpendicular to the optical axis direction ofthe projection optical system.

In the first scanning exposure direction, the focusing control mode tobe used when said pattern is transferred might be decided, furtherconsidering a shape of an illumination area on said substrate.Alternatively, the focusing control mode can be decided, prior to thetransfer operation for the divided area. In this case, the focusingcontrol mode for the substrate is decided depending on the relationbetween the surface condition of the divided area and the shape of theillumination area (the exposure area). Then, the pattern formed on themask can be transferred onto the divided area, performing the focusingcontrol in the properly adjusted mode.

The leveling control can be done or not done by taking notice of that inthe synchronous moving direction, in which it is predicted that thedriving load becomes the highest when the focusing control is performed.That is, the plurality of focusing control mode include: the first modein which the tilt control of the substrate is performed in thesynchronous moving direction by following-up the synchronous moving; anda second mode in which tilt control of the substrate is not performed inthe synchronous moving direction by following-up the synchronous moving.

Furthermore, the surface condition of the divided area can berepresented as a spatial frequency distribution along the synchronousmoving direction of the substrate, on which a repeating unit area of thepattern to be transferred having convex and concave along the opticalaxis direction of the projection optical system, wherein the repeatingunit area is placed in said divided area; and the shape of theillumination area is represented as a slit width of the illuminationarea in the synchronous moving direction of the substrate. Then, thesubstrate can be controlled by the focusing control in the first mode orthe second mode. The first mode is used, when a predominant wavelengthis equal to or longer than the length depending on the slit width,wherein the predominant wavelength is corresponding to a predominantfrequency, which has maximum amplitude in said spatial frequencydistribution. The second mode is used, when a predominant wavelength isshorter than the length depending on the slit width. In this case, theleveling control in the synchronous direction can be the suitablecontrol that neither has serious deterioration of the imagingperformance nor requires high focusing control power, when the highdriving load is supposed to be necessary for the focusing control.

The length depending on the slit width can be the slit width.

In the first scanning exposure method, for example, the surfacecondition of the divided area can be obtained by calculating based onthe lithography process for the substrate, or can be measured prior tothe transfer of the pattern formed on the mask onto the divided area.

Such a prior measurement can be conducted in every lot of the substrate,prior to the transfer of the pattern. Alternatively, it can be done inevery exposure process, prior to the transfer of the pattern.Furthermore, when a plurality of the divided areas are arranged on thesubstrate, the prior measurement for the surface condition of thesubstrate can be representatively conducted for one of the dividedareas. In the above-mentioned cases, the time to be spent the priormeasurement can be shorten without the large transfer error of thepattern, compared to perform the prior measurement for the surfacecondition of every divided area.

In the first scanning exposure method, the focusing control mightinclude a focus position control that controls a position of saidsubstrate in an optical axis direction of said projection opticalsystem; on a decision that said focus position control can not follow-upsaid synchronous moving, a control, wherein a position of the substratein an optical axis direction of said projection optical system justprior to the decision is maintained, is performed. In this case, thepattern formed on the mask is transferred onto the substrate with noserious deterioration of the imaging performance or no premise for thehigh driving power for the focusing control.

In the first scanning exposure method, the focusing control can includea tilt control of the substrate in the synchronous moving direction; ona decision that the tilt control can not follow-up said synchronousmoving, a control, wherein a position of the substrate in an opticalaxis direction of said projection optical system just prior to thedecision is maintained, is performed. When it is decided that thesynchronous moving can be followed-up the tilt control, the tilt controlis performed by following the synchronous moving. In this case, theleveling control in the synchronous direction can be the suitablecontrol that neither has serious deterioration of the imagingperformance nor requires high focusing control power, when the highdriving load is supposed to be necessary for focusing control.

Alternatively, in the first scanning exposure method, the said focusingcontrol includes a tilt control that controls the tilt of the substrate,wherein the substrate is moved in a plane perpendicular to the opticalaxis direction of the projection optical system and the tilt of thesubstrate in a direction perpendicular to the synchronous movingdirection is controlled; on a decision that the tilt control can notfollow-up said synchronous moving, a control, wherein a position of thesubstrate in an optical axis direction of said projection optical systemjust prior to the decision is maintained, is performed. When it isdecided that the synchronous moving can be followed-up the tilt control,the tilt control is performed by following the synchronous moving. Inthis case, the leveling control in the synchronous direction can be thesuitable control that neither has serious deterioration of the imagingperformance nor requires high focusing control power, when the highdriving load is supposed to be necessary for the focusing control.

In the second aspect of the present invention, the present invention isthe second scanning exposure method for exposing the substrate, whilemoving the substrate in a predetermined direction to an exposure beamwhich passes through the projection optical system, and detecting aposition information of the substrate surface in the optical axisdirection of the projection optical system comprising the steps of:measuring convex and concave information on the substrate surface, whilemoving the substrate in the predetermined direction in a condition thatthe substrate is not exposed; and deciding whether a tilt of thesubstrate in the predetermined direction is adjusted or not, during anexposure of the substrate, by using said a convex and concaveinformation measured, wherein based on said position informationdetected.

With this, while the substrate is moved into the predetermined directionwith no exposure, the information of the concave and convex on thesubstrate surface is measured. Based on the detection result of theconcave and convex, it is decided whether a tilt of the substrate in thepredetermined direction, which is obtained from the position informationof the substrate surface in the optical axis direction of the projectionoptical system, is adjusted or not. Accordingly, the pattern formed onthe mask might be transferred onto the substrate, performing thesuitable focusing control depending on the surface condition of thedivided area.

In the second scanning exposure method of the present invention, it canbe decided whether a tilt of the substrate in the predetermineddirection is adjusted or not during an exposure of the substrate so thata deterioration of positioning accuracy of the image plane of saidprojection system and the substrate surface is prevented. In this case,the properly adjusted focusing control action might be performed,depending on the surface condition of the divided area in which thewarpage or swell of the raw substrate is reflected. Therefore, thepattern formed on the mask is transferred onto the substrate with noserious deterioration of the imaging performance or no premise for thehigh driving power for the focusing control.

In the third aspect of the present invention, the present invention isthe scanning exposure apparatus which is used to transfer the patternformed on the mask onto the divided area on the substrate, through aprojection optical system, moving the mask and the substrate,comprising: a mask stage for holding the mask; a substrate stage forholding the substrate; the first detecting system for detecting aposition for at least one of detection point in an optical axisdirection of the projection optical system, in a illumination area onsaid substrate surface; the first driving system for driving the maskstage and the substrate stage in plane perpendicular to the optical axisdirection of the projection optical system; the second driving systemfor driving the substrate stage to at least one of the optical axisdirection of the projection detecting system and the tilt direction; amemory unit for storing a data representing the substrate condition ofthe divided area; and a control system for synchronously moving the maskstage and the substrate stage by controlling the first driving system,while performing said focusing control by controlling the second drivingsystem based on a result from the first detecting system, wherein afocusing control mode to be used in the transfer a pattern onto saiddivided area is decided from a plurality of focusing control modes basedon the data representing the substrate surface of the divided area.

According to this, the control system decides a focusing control modebased on a relation between a data representing the substrate surface ofthe divided area and a data for the shape of the illumination area.Then, the control system controls the second driving system in thedecided focusing control mode, based on the detection result from thefirst detecting system to drive the substrate stage for holding thesubstrate into the optical axis direction of the projection opticalsystem, to performs the focusing control. In company with the focusingcontrol, the control system controls the first driving system to performsynchronous moving control of the mask stage and the substrate stage;thereby the pattern formed on the mask is transferred onto the dividedarea on the substrate through the projection optical system.Accordingly, the pattern is transferred by using the present exposuremethod, it can be transferred without serious deterioration of theimaging performance, while the focus control is performed by using thesimple structure which does not promise the high focusing drivingpracticability. Alternatively, the control system can be structured sothat the focusing control mode is decided, prior to the transferoperation for the divided area.

In the focusing control, the structure might be used; wherein thecontrol system performs the focus position control, which control is thesecond driving system by using the detection result from the firstdetecting system according to the decided focusing control mode, and itincludes the focusing control for controlling the substrate position inthe optical axis direction of the projection optical system. The otherstructure might be used; wherein the first detecting system fordetecting the position of the multiple detection points, and the controlsystem for performing the focusing control including the levelingcontrol. In the first detecting system, the multiple detection pointsinclude at least two detection points in the illumination area on thesubstrate, and the positions of them in the optical axis direction ofthe projection optical system are detected. The leveling controlcontrols the second driving system by using the detection result fromthe first detecting system according to the decided focusing controlmode, and it controls the tilt of the substrate to the planeperpendicular to the optical axis direction of the optical projectionsystem.

In the leveling control, the structure might be used: wherein the firstdetecting system detects the positions of the multiple detection pointsin the illumination area on the substrate surface in the optical axisdirection of the projection optical system; and the multiple detectionpoints include at least two points, of which positions in thesynchronous moving direction are different. The control system controlsthe second driving system by using the detection result from the firstdetecting system according to the decided focusing control mode toperform leveling control including the tilt control of the substrate inthe synchronous moving direction. Furthermore, another structure mightbe used; wherein the first detecting system detects the positions of themultiple detection points in the illumination area on the substratesurface in the optical axis direction of the projection optical system;and the multiple detection points include at least two points, of whichpositions in the direction perpendicular to the synchronous movingdirection are different. The control system controls the second drivingsystem by using the detection result from the first detecting systemaccording to the decided focusing control mode to perform the levelingcontrol including the tilt control of the substrate in the planeperpendicular to the synchronous moving direction.

In the scanning exposure apparatus of the present invention, theabove-mentioned control system might be the structure for deciding thefocusing control mode based on the relation between the datarepresenting the surface condition of the divided area and that for theshape of the illumination area. In this case, since the focusing controlmode is decided, further considering the shape of the illumination areaon the substrate surface, the suitable focusing mode is preciselydecided.

The plurality of focusing control modes can be include: the first modefor controlling a tilt of the substrate in the synchronous movingdirection by following-up the synchronous moving of the substrate; andthe second mode for not controlling the tilt of the substrate in thesynchronous moving direction by following-up the synchronous moving ofsaid substrate. Furthermore, the following structure can be used:wherein, the data representing the substrate surface on the divided areais a predominant wavelength corresponding to a predominant frequency, ofwhich amplitude is maximal in a spatial frequency distribution. Thedistribution shows a repeating unit area for the pattern to betransferred in the divided area having a convex and concave on thesubstrate. Wherein, the convex and concave are in the synchronousdirection. The data for the shape of the illumination area is a slitwidth in the synchronous moving direction of the illumination area; andthe control system performs the focusing control of the substrate in thefirst mode when the predominant wavelength is not shorter than the slitwidth, and it performs the focusing control of the substrate in thesecond mode when the predominant wavelength is shorter than the slitwidth.

The scanning exposure apparatus can be further comprise the seconddetecting system which detects a tilt of the substrate stage in thesynchronous moving direction to a virtual plane perpendicular to theoptical axis direction of the projection optical system and in adirection perpendicular to the said synchronous moving direction; andthe main control system can perform the focusing control based ondetection results from the first and second detecting systems. Withthis, when the suitable focusing control can be performed by using thedetection result from the first detecting system, the suitable focusingcontrol can be performed by further considering the detection resultfrom the second detecting system.

The following structure can be used: when a plurality of focusingcontrol modes further includes a third mode, which maintains the surfaceof the substrate shape in parallel with the virtual plane based on thedetection result from the second detecting system. The exposureapparatus further comprises the calculating operation unit, whichacquires the detection result data from the first detecting systemduring the synchronous moving under the focusing control in the thirdmode and then obtain the surface condition of the divided area, based onthe detection result data. In this case, adding to the general exposureprocessing, the measurement processing for the surface condition of thedivided area prior to the scanning exposure by itself. Alternatively,the calculating operation unit employs the structure; wherein thecalculating operation unit calculates the spatial frequency distributionformed by the concave and convex along the synchronous moving directionof the substrate, and the calculating operation units obtains apredominant wavelength corresponding to a predominant frequency whichbecomes maximum in the spatial frequency distribution to store in thememory unit, and then an calculating operation system for acquiring adetection result data by using the first detecting system during saidsynchronous moving under the focusing control in the third mode, and itobtains the surface condition of the divided area based on the detectionresult data. Wherein, the concave and convex in the optical axisdirection of the projection optical system are formed in the area forrepeating unit of a pattern to be transferred in the divided area.

In the fourth aspect of the present invention, the present invention isa making method of a scanning exposure apparatus for transferring thepattern formed on the mask through a projection optical system, while amask and a substrate move synchronously, comprising the steps of:providing a mask stage for holding the mask; providing a substrate stagefor holding the substrate; providing a first detecting system fordetecting a position of the projection optical system in an optical axisdirection in at least one detection point in said illumination area onthe substrate surface; providing a first driving system for driving themask stage and the substrate stage in a plane which is perpendicular tothe optical axis direction of the projection optical system; providing asecond driving system for driving the substrate stage in at least onedirection of the optical axis direction of the projection optical systemor a tilt direction; providing a memory unit for memorizing a datarepresenting a surface condition of the divided area; and providing acontrol system for moving the mask stage and the substrate stagesynchronously by controlling the first driving system, performing thefocusing control by controlling the second driving system based on aresult from the first detecting system. Alternatively, the controlsystem can use the structure in which the focusing control mode isdecided, prior to the transfer operation for the divided area.

With this, the exposure apparatus of the present embodiment might beproduced; wherein, the above-mentioned mask stage, the substrate stage,the first detecting system, the first driving system, the second drivingsystem, the memory unit, control system, and other blocks and units, andare connected electrically, mechanically and optically to assemble theapparatus. After that, the apparatus is totally adjusted (electricaladjustment or inspection of the operation).

The making method of the scanning type exposure apparatus of the presentinvention can further comprise the step of providing the seconddetecting system for detecting a tilt of the substrate stage in thesynchronous moving direction to a virtual plane perpendicular to theoptical axis direction of the projection optical system and in adirection perpendicular to the synchronous moving direction. In thiscase, the apparatus for performing the suitable focusing control can bemade, which performs the suitable focusing control by considering thedetection result from the second detecting system, even when thesuitable focusing control can not be performed based on the soledetection result from the first detection system.

The making method of the scanning type exposure apparatus of the presentinvention for providing the second detecting system might furthercomprise the step of providing a calculating operation system foracquiring a detection result data from the first detecting system duringthe synchronous moving under the focusing control, which maintains thesubstrate stage surface to be substantially parallel to the virtualplane, based on the detection result from the second detecting system toobtain the surface condition of the divided area.

Furthermore, in the lithography step, the device comprising finepatterns may be manufactured by transferring a predetermined pattern tothe divided area formed on the substrate by using the apparatus of thepresent invention. At that time, the exposure method in which the firstor the second position detection method described above is used.Accordingly, the present invention is the device manufactured by usingthe exposure apparatus of the present invention in another viewpoint,and also it is the manufacturing method of device by using the exposuremethod of the present invention to transfer the predetermined patternonto the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing the schematic arrangement of an exposureapparatus according to one embodiment;

FIG. 2 is a view for explaining the substrate table and its drivingmechanism of the apparatus in FIG. 1;

FIGS. 3A and 3B are perspective views for explaining the principle offocus shown in FIG. 1;

FIG. 4 is a view showing respective sensor, which structures the focussensor in FIG. 1;

FIG. 5 is a block diagram showing the focus control system of FIG. 1;

FIG. 6 is a view showing as an example of structure of the control modedeciding block;

FIG. 7 is a flow chart for explaining the exposure operation;

FIGS. 8A and 8B are a view showing the measurement result of the spatialfrequency distribution and the preferential wavelength;

FIGS. 9A and 9B are views for explaining defocus amount at one point onthe wafer;

FIG. 10 is a flow chart for explaining the device manufacturing methodby using the exposure apparatus shown in FIG. 1; and

FIG. 11 is a flow chart showing the processing step in FIG. 10.

BEST MODE FOR CARRYING OUT THE INVENTION

An exposure method and exposure apparatus according to an embodiment ofthe present invention will be described below with reference to FIGS. 1to 11.

FIG. 1 shows the schematic arrangement of an exposure apparatus 100according to one embodiment of the present invention.

The exposure apparatus 100 comprises: the reticle stage 3 serving as amask stage for holding the reticle R as a mask; a projection opticalsystem PL; the substrate table 10 as a substrate stage for holding thewafer W as a substrate; X-Y stage 11 for loading the substrate table 10;the focus sensors 7A and 7B as the first detecting system; the controlsystem for controlling thereof, and so forth.

The reticle R is fixed on the reticle stage 3 through the reticle holder2. The reticle stage 3 is driven in a synchronous moving direction (thescan direction is Y-direction shown in FIG. 1) along a guide face of thereticle stage guide 4 by the reticle stage driving block 14 which useselectromagnetic force such as a linear motor and so forth. On thereticle stage 3, the moving mirror 5 is provided in the one terminal ofits moving direction. The reticle interferometer is arranged foremitting laser beams to the moving mirror 15 to receive their reflectedlights and measuring the position of the reticle stage 3 in theY-direction and the yawing amount. The reticle interferometer 13 canmeasure the position of the reticle stage in X-direction by using themoving mirror provided on the reticle stage 3 which is not shown inFigs. Various measured by the reticle interferometer 13 are inputtedinto the main control system 20, which controls the position and thevelocity of the reticle stage 3 through the reticle driving block basedon the value.

The illumination area 1 on the reticle R is illuminated almost evenly bythe illumination lights from the illumination system, which is notshown. The projection image is formed on the exposure area 6 as theillumination area formed on the wafer W through the projection opticalsystem PL.

The illumination system includes, for example, the light unit, ashutter, the secondary light source forming optical system, a beamsplitter, a condenser lens system, a reticle blind, and an image lenssystem, which are not shown in FIG. 1. The respective components of theillumination system are disclosed, for example, disclosed in thepublication of Japanese unexamined patent application (refer to as“Japan laid-open”, hereinafter) No. H9-320956. The disclosure describedin the above is fully incorporated by reference herein. As the lightsource unit, followings are used: KrF excimer laser beam (wavelength=248nm), ArF excimer laser beam (wavelength=193 nm), F₂ laser beam(wavelength=157 nm), Kr₂ (krypton dimer) laser beam (wavelength=146 nm),Ar₂ (argon dimer) laser beam (wavelength=126 nm), high harmonicgeneration devices such as copper vapor laser or YAG laser harmonics, anultra-high pressure mercury vapor lamp (e.g., g-line or i-line), or thelike. Alternatively, instead of the light, which is emitted from theabove-mentioned light source, beam such as charged electron x-ray andelectron beam might be used.

The wafer holder 8 is fixed on the substrate table 10, for example, byvacuum chucking which is not shown. The substrate table 10 is supportedon the X-Y stage by three shafts, 21, 22 and 23, all of which are theZ-position driving blocks as the second driving system, as shown in FIG.2. These the Z-position driving blocks 21, 22 and 23 are composed ofthree actuators, 21A, 22A and 23A and three encoders, 21B, 22B and 23B(see FIG. 5). The Z-position driving blocks drives the respectivesupporting shafts of the blocks structured in the undersurface of thesubstrate table 10 in the optical axis direction of the projectionoptical system PL (Z-direction). The encoders detect the position of therespective position driving blocks in Z-direction. The structure of theZ-position driving block is disclosed, for example, Japan laid-open No.H9-82636 and its correspondent, U.S. Pat. No. 5,737,063 The disclosuredescribed in the above is fully incorporated by reference herein, as faras the law of the countries designated in a request or elected in ademand for the application filed in the country of origin permits them.

In the present embodiment, the Z-leveling stage 60 as the adjustingmeans for adjusting both the position in the optical axis direction(Z-direction position) and the tilt of the wafer W surface is composedof the substrate table 10 and three actuators 21A, 22A and 23A (see FIG.2).

Back to FIG. 1, the X-Y stage on which the substrate table is fixed isdriven by the wafer stage driving block 16 which utilize electromagneticforce such as the linear motor to move wafer in X-Y two dimensionaldirection. The first driving system is composed of the reticle stagedriving block 14 and the wafer stage driving block 16. As shown in FIG.2, in one end of the substrate table 10 in X-axis direction, the movingmirror 12 X is placed along the end, i.e., Y-axis. The waferinterferometer for X-axis 15X is arranged opposite to the moving mirror12X. Similarly to this, in one end of the substrate table 10 in Y-axisdirection, the moving mirror 12 Y is placed along the end, i.e., X-axis.The wafer interferometer for Y-axis 15Y is arranged opposite to themoving mirror 12Y. X-Y two dimensional position of the substrate table10 is measured by the waver interferometers 15X and 15Y. In FIG. 1, themoving mirrors 12X and 12Y are represented as the moving mirror 12, andthe wafer interferometers 15X and 15Y are represented as the waferinterferometer. The measured value is input into the main control system20, which controls the position and the velocity of the X-Y stage 11 byusing the measured value through the wafer stage driving block 16. Inthe exposure the wafer W, the main control system 20 synchronouslycontrols the reticle stage 3 and the X-Y stage 11 based on the measuredvalue derived from the reticle interferometer 13 and the waferinterferometer 15.

The above mentioned focus sensors 7A and 7B (to be generally referred toas the “focus sensor 7”) as composed of the emitting and/or transmittinglight system 7A and the light sensing system, and they detect theposition in Z-direction of the wafer W surface. In FIG. 3, the detectionprincipal in the focus sensor 7 is shown. As shown in FIG. 3A, when thelight beam is emitted from the emitting and/or transmitting light system7A, the incident position of the reflection light on the wafer W surfaceis changed on the light sensing plane of the light sensing system 7Bdepending on the position of the wafer W surface in Z-direction.Corresponding to the change, S-shaped curve signal as shown in FIG. 3Bis output from the light sensing system 7B, and the position of thewafer W surface in Z-direction is detected based on the S-shaped curvesignal. In the present invention, the focus sensor 7 is structured bythe plural sensors for detecting the position in Z-direction of pluraldetection points 7 ₁ to 7 _(n), as shown in FIG. 4. Since the sensorsare corresponding to the detection points 7 ₁ to 7 _(n) respectively,they are referred to as the “sensor 7 _(i) (i=1 to n)”, as needed. Theplural sensors 7 ₁ to 7 _(n) are arranged two dimensionally in theexposure area 6 on the wafer W, and its center is the optical axisdirection of the projection light system PL. The plural sensors 7 ₁ to 7_(n) detect the plural positions in Z-direction to obtain theapproximate plane by using the operation processing such as theleast-square method. From the tilt of the approximate plane, the tiltangle (θ_(X), θ_(Y)) of the wafer W surface is also obtained. Thedetailed structure of the focus sensor is disclosed, for example, Japanlaid-open No. H6-283403 and its correspondent, U.S. Pat. No. 5,448,332.The disclosure described in the above is fully incorporated by referenceherein, as far as the law of the countries designated in a request orelected in a demand for the application filed in the country of originpermits them.

In the present embodiment, the sensors 7 ₁ to 7 _(n) are used fordetecting the tilt angle and the defocus amount (the position inZ-direction) of the wafer W surface. However, instead of the pluralsensors, AF sensors, which has one determination point, might be used.In this case, the leveling sensor with the parallel light beams diagonalincident manner. In the sensor, the parallel light beam is diagonallyemitted to the wafer W surface, and the tilt angle of the surface isdetected by using the transversal shift amount for the condense positionof the reflection light.

In FIG. 1, the main controller system 20 controls the Z-leveling stage60 (more particularly, three actuators 21A, 22A, and 23A) for drivingthe substrate table 10, to control the position of the wafer surfacebased on the measured value from the focus sensor 7.

The substrate table 10 is driven by the above-mentioned actuators 21A,22A and 23A, and the positions of the supporting points for thesubstrate table 10 in Z-direction are measured by the encoders 21B, 22Band 23B, which are incorporated into the Z-position driving blocks 21,22 and 23. The position of the substrate table 10 is defined by themeasured values shown as PZ1, PZ2 and PZ3), and X-Y two dimensionalcoordinate position of the Z-position driving blocks 21, 22, and 23shown as (X₁, Y₁), (X₂, Y₂) and (X₃, Y₃). $\begin{matrix}{\begin{bmatrix}\Theta_{X} \\\Theta_{Y} \\Z\end{bmatrix} = {\begin{bmatrix}X_{1} & Y_{1} & 1 \\X_{2} & Y_{2} & 1 \\X_{3} & Y_{3} & 1\end{bmatrix}^{- 1} \cdot \begin{bmatrix}{PZ1} \\{PZ2} \\{PZ3}\end{bmatrix}}} & (1)\end{matrix}$

Wherein Θ_(X), Θ_(Y) and Z are as follows:

Θ_(X): tilt in X-direction (tilt around Y-axis)

Θ_(Y): tilt in X-direction (tilt around Y-axis)

Z: the position in Z-direction

In the coordinate system or the surface of the wafer W by using thefocus sensor 7 and that of the substrate table 10 by using the encoder21B, 22B and 23B, their origins and scales are coincident by thecalibration previously preformed.

In FIG. 5, the structure of the focus control in the present embodimentis shown. In the focus control system comprises: the control modedeciding block 41, the target value outputting block 25, the lest-squareapproximately block 27, the control mode determining block 28, theinterdependence freeing unit 20, the coordinate transformation effectingblock 30, the controller 31, the multiplexer 32, three subtractor 33A to33C, and the predominant wavelength operating block 43, a shown in FIG.5. The respective blocks are explained hereinafter in detail. Thecontrol mode deciding block 41 outputs either “0” and “1” as the modedesignation signal MD0 mode to the target value outputting block 25 andthe control mode to the target value outputting block 25 and the controlmode determining block 28. When the predominant wavelength value λ₀,which is referred in the exposure to be performed, is stored in thememory unit 19, “0” is out put. When the predominant wavelength value λ₀is not stored in the memory unit 19, “1” is output. Furthermore, thecontrol mode deciding block 41 out put either “0” or “1” as the modedesignation signal MD1 to the target value outputting block 25 and thecontrol mode determining block 28, based on the predominant wavelengthvalue λ₀ which is stored in the memory unit 19 and the width value L₀ ofthe exposure area 6 in Y-direction which is input from the I/O unit 18.

When the λ₀>L₀, “0” is output as the mode designation signal MD1.

When the λ₀<L₀, “1” is output as the mode designation signal MD1. As thewidth value L₀ of the exposure area 6 in Y-direction, the stored valuein the memory unit 19 might be used, until it is once input from the I/Ounit 18 to be stored in the memory unit 19 and it is again input fromthe I/O unit 18.

The target data outputting block 25 always transmits the first targetvalue in Z-direction z′, the first target value for the tilt inX-direction (the tilt around Y-axis) θ_(X)′, and the second target valuefor the tilt in Y-direction (the tilt around X-axis) θ_(Y)′. The targetdata outputting block 25 also outputs the first target value inZ-direction position z′ as a target value for the positional control bythe controller 31, when (0, 0) is input as the mode designation signal(MD0, MD1). Simultaneously, depending to the result of the control modedetermining mentioned hereinbelow, the target data outputting block 25outputs the first target value of the tilt in X-direction (the tiltaround Y-axis) θ_(X)′ or the second target value Θ_(X)′, and firsttarget value of the tilt in Y-direction (the tilt around X-axis) θ_(Y)′or the second target data Θ_(Y)′ as the target value for the positionalcontrol to be performed by the controller 31. Wherein, the first targetvalue of the tilt in X-direction (the tilt around Y-axis) θ_(X)′, andfirst target value of the tilt in Y-direction (the tilt around X-axis)θ_(Y)′ are inherent target value for the focus control obtained by thecalibration such as proof prints of the image plane of the projectionoptical system PL. The second target data Θ_(X)′ and Θ_(Y)′ are setvalue for convenience to maintain the tilt in X-direction (the tiltaround Y-axis) and Y-direction (the tilt around X-axis).

The target data outputting block 25 outputs the first target value inZ-direction position z′ as a target value for the positional control bythe controller 31, when (0, 1) is input as the mode designation signal(MD0, MD1). Simultaneously, depending to the result of the control modedetermining mentioned hereinafter, the target data outputting block 25outputs the first target value of the tilt in X-direction (the tiltaround Y-axis) θ_(X)′ or the second target value Θ_(X)′, and firsttarget value of the tilt in Y-direction (the tilt around X-axis) θ_(Y)′or the second target data Θ_(Y)′ as the target value for the positionalcontrol to be performed by the controller 31.

As described above, when the mode designation signal MD0 is “0”, thetilt of the substrate table 10 immediately before switching the controlmode is used as the second target position Θ_(X)′ and Θ_(Y)′.

The target data outputting block 25 outputs the second target value inZ-direction position, z′ as the target value for the positional controlby the controller 31, when (1, 0) is input as the mode designationsignal (MD0, MD1). Simultaneously, the target data outputting block 25outputs the second target value of the tilt in X-direction (the tiltaround Y-axis) Θ_(X)′, and second target value of the tilt inY-direction (the tilt around X-axis) Θ_(Y)′ as the target value for thepositional control to be performed by the controller 31.

As described above, when the mode designation signal MD1 is “1”, thecertain value at which the substrate table 10 is horizontal is used asthe second target position Z′, Θ_(X), and Θ_(Y).

The least-square approximating block 27 performs the plane approximationthe detected signals of the wafer W surface position in Z-directiondetected by the respective sensor 7 ₁ to 7 _(n) which are comprising thefocus sensor 7 to obtain three components z, θ_(X) and θ_(Y). Thecomponent z shows the wafer W surface position on the optical axis AX ofthe projection detecting system PL in Z-direction, θ_(X) shows the tiltin X-direction (the tilt around Y-axis), and θ_(Y) shows the tilt inY-direction (the tilt around X-axis).

As shown in FIG. 6, the control mode determining block 28 comprises thesubtractors, 35X, 35Y, and 35Z, the determination processing block 36,and the logical processing circuit ANDX, ANDY and INVZ. The subtractorsoperate the deviation (Δz, Δθ_(X), and Δθ_(Y)) between the target valuez′, θ_(X)′, and θ_(Y)′ obtained from the target data outputting block 25and the current information z, θ_(X), and θ_(Y) obtained from theleast-square approximation block 27. The determination processing block36 for performing the determination processing of the control modedescribed hereinafter by using the deviation (Δz, Δθ_(X), and Δθ_(Y))and the value of the mode designation signal (MD0, MD1). The logicaloperation circuits output the control designation signals SL_(X),SL_(Y), and SL_(Z). The control designation signals SL_(X) and SL_(Y),are output to both the target data outputting block 25 and themultiplexer 32, and the control designation signals SL_(Z) is output tothe multiplexer 32.

From the logical operation unit ANDX, when the mode designation signalMD0 is “0”, the operation result SL_(X)′ which is output from thedetermination processing block 36 is output as the control designationsignal SL_(X). When the mode designation signal MD0 is “1”, “0” isoutput as the designation signal SL_(X). From the logical operation unitANDY, when the mode designation signal (MD0, MD1) is (0, 0), theoperation result SL_(Y)′ which is output from the determinationprocessing block 36 is output as the control designation signal SL_(Y).When the mode designation signal (MD0, MD1) is not (0, 0), “0” is outputas the designation signal SL_(Y). From the logical operation unit INVZ,the inverted signal of the mode designation signal MD0 is output as theSL_(Z).

In order to structure the control mode determining block 28, n FIG. 6,the logical operation circuits, ANDX, ANDY, and INVZ are arranged on thelast step of the output for the control designation signals SL_(X),SL_(Y) and SL_(Z). However, another structure might be employed. Forexample, the deviation (Δz, Δθ_(X), and Δθ_(Y)) and the mode designationsignal (MD0, MD1) are input into the determining processing block 36,which performs the operation so that the output value is almost the sameas SL_(X), SL_(Y) and SL_(Z).

A coordinate transformation effecting block 30 performs the coordinatetransformation of the measured values, PZ1, PZ2, and PZ3 into Z for theposition in Z-direction, the tilt in X-direction (the tilt aroundY-axis), and the tilt in Y-direction (the tilt around X-axis) accordingto the equation (1) to output the multiplexer 32 and the target dataoutputting block 25. Wherein, PZ1 to PZ3 are obtained by using theencoders 21B, 22B and 23B, which are respectively incorporated in threeZ-position driving blocks 21, 22 and 23.

The subtractors 33A to 33C respectively obtain the position deviation inZ-direction Δzz, the tilt deviation in X-direction (the tilt aroundY-axis) Δθ_(XX), the tilt deviation in Y-direction (the tilt aroundX-axis) Δθ_(YY). Wherein, the deviation Δzz represents the differencebetween the target value z′ (or Z′) from the target data outputtingblock 25 and the actual value z (or Z). The deviation Δθ_(XX) representsthe difference between the target value θ_(X)′ (or Θ_(X)′) from thetarget data outputting block 25 and the actual value θ_(X) (or Θ_(X))output from the multiplexer 32. The deviation Δθ_(YY) represents thedifference between the target value θ_(Y)′ (or Θ_(Y)′) from the targetdata outputting block 25 and the actual value θ_(Y) (or Θ_(Y)) outputfrom the multiplexer 32.

The above-mentioned controller 31 is a controller for the positionalcontrol loop, and it comprises PID control unit, which performs Paction, PI action, or PID action by using the above-mentioned positiondeviation, the position deviation in Z-direction Δzz, the tilt deviationin X-direction (the tilt around Y-axis) Δθ_(XX), and the tilt deviationin Y-direction (the tilt around X-axis) Δθ_(YY), are used as the actionsignals. This controller 31 gives the gained deviation Δzz, Δθ_(XX), andΔθ_(YY), as velocity instruction to the actuators, 21A, 22A and 23A.

The above-mentioned interdependence freeing unit 29 depends on thelinearity, however, by inserting this into the servo loop, threecomponents such as the component in Z-direction and the components intilt direction around X- or Y-axis might be independently controlled.The interdependence freeing unit 29 performs the interdependence freeingoperation for distributing the given velocity instruction as threecomponents in the tilt around X- and Y-axis, and the position inZ-direction by using the X-Y two dimensional coordinate value of thecurrent position for the respective Z-position driving block. Then, itactually outputs the operation result to the actuators 21A, 22A and 23A.

The above-mentioned multiplexer 32 outputs either the set of threecomponents of the current value (z, θ_(X), θ_(Y)) from the least-squareapproximation block 27 or those of the current value (Z, Θ_(X), Θ_(Y)),depending on the control mode designation signal SL_(X), SL_(Y), andSL_(Z). In the multiplexer 32, when the respective control modedesignation signal, SL_(X), SL_(Y), and SL_(Z) is “1”, the current valueis output from the least-square approximation block 27. On the contrary,when the respective control mode designation signal, SL_(X), SL_(Y), andSL_(Z) is “0”, the current value from the coordinate transformationeffecting potion 30.

According to the above-mentioned structure, the focusing control iscarried out in the first focusing control mode, when the modedesignation signal (MD0, MD1) is (0, 0). In the first mode of thefocusing control, the main control system 20 follows-up the changes ofthe three component value (z, θ_(X), θ_(Y)) from the least-squareapproximation block 27 generated during the synchronous movement to theutmost. In the focus control system, the focusing control is carried outin the second focusing control mode, when the mode designation signal(MD0, MD1) is (0, 1). In the second mode of the focusing control, themain control system 20 follows-up the changes of the two component value(z, θ_(X)) from the least-square approximation block 27 generated duringthe synchronous movement to the utmost, but it does not follow-up thechange of the component (θ_(Y)). Furthermore, in the focus controlsystem, the focusing control is carried out in the third focusingcontrol mode, when the mode designation signal (MD0, MD1) is (1, 0). Inthe third mode of the focusing control, the main control system 20 doesnot follow-up the changes of the component value (z, θ_(X), θ_(Y)) fromthe least-square approximation block 27 while they are synchronouslymoved.

The above-mentioned three shafts actuators, 21A to 23A have the velocityminor loops (the current minor loop), and allow the Z-position drivingblocks 21, 22, and 23 to follow-up the given velocity instruction byusing the built-in velocity detector (the tacho generator) with theservo control. That is, the Z-position driving blocks 21, 22 and 23 arestructured as the subunit controlled by using the velocity loop in whichthe built-in tacho generators in the actuators 21A, 22A and 23A are usedas the velocity sensors. Therefore, the Z-position driving block mighttrack according to the given velocity instruction.

The above-mentioned predominant wavelength operating block 43 acquiresthe data DT₁ to DT_(n), and obtain the predominant wavelength λ₀ tostore it in the memory unit 19. XY positions of the substrate table 10from the wafer interferometer 15 and positions of the wafer W surface inZ-direction are corresponding, in the data DT₁ to DT_(n).

Referring to FIGS. 7 to 9, the exposure procedure of the presentinvention is explained.

First of al, in step 101 on FIG. 7, the wafer W is loaded on thesubstrate table 10 by the wafer loader to expose. Subsequently, in step103, the main control system 20 decides whether it is the first processor not from the point of view of the exposure condition (the processcondition) including the pattern formation history on the wafer W, andkinds of the photoresist agents; that is, the predominant frequency λ₀as the information for the surface condition of the shot area on thewafer W has been stored in the memory unit 19, prior to the exposure ofthe wafer. In step 103, when the main control system decides that it isthe first process, the procedure goes to step 105 and the control modedeciding block 41 outputs (1, 0) as the mode designation signal (MD0,MD1) to set the focusing mode in the third mode. The target dataoutputting block 25 inputs the control mode deciding block, and itoutputs the certain value for being the surface of the substrate table10 horizontal as the target positions Z′, Θ_(X)′, Θ_(Y)′ to thesubtractor 33A, 33B and 33C. The control mode determining block 28outputs (0, 0, 0) as the control mode signal (SL_(X), SL_(Y), SL_(Z)),and the multiplexer 32 which received the signal outputs threecomponents of the current value (Z, Θ_(X)′, Θ_(Y)′) from the coordinatetransformation effecting block 30. Consequently, the focusing control isperformed so that the surface of the substrate table 10 is almosthorizontal.

Then, in step 107, the information for the surface condition of the shotarea on the wafer W, i.e., the predominant frequency λ₀ is measured. Inthe measurement, the main control system moves the substrate table 10for one shot area to the synchronous moving direction (+Y or −Ydirection) through the wafer stage driving block 16, maintaining thefocusing mode in the third mode, i.e., being the surface of thesubstrate table 10 horizontal. In the present embodiment, the movementof the substrate table 10 is similarly controlled by the main controlsystem 20 except it instructs to the illumination system which is notshown not so as to emit the illumination light for the exposure. Thatis, the shot area on the wafer W is moved against the exposure area 6(the plural detection points for the focus sensor 7) in the conditionwithout exposing the wafer W. The movement might be the moving mannerdifferent from the synchronous moving in the scanning exposure.

During this movement, the predominant wavelength operating block 43acquires the data, in which XY positions of the substrate table 10 fromthe wafer interferometer 15 is corresponding to positions of the wafer Wsurface in Z-direction. Then, the predominant wavelength operating block43 performs the spatial frequency analysis for the synchronous movingdirection based on the acquired data to obtain the spatial frequencydistribution as the information for the convex and concave of the shotarea in the synchronous moving direction. In FIG. 8, examples of thespatial frequency distribution thus obtained are shown. The predominantwavelength λ₀ corresponds to the predominant frequency is obtained, andthe amplitude of the predominant frequency is maximum at the spatialfrequency distribution (see FIG. 8). The predominant wavelengthoperating block 43 stores the predominant wavelength λ₀ thus obtainedand the process condition into the memory unit.

As mentioned above, when the measurement of the predominant wavelengthλ₀ is completed. Then the procedure goes to step 109. In theabove-mentioned step 103, when the main controller decides that it isnot the first step, the procedure goes to directly step 109, skippingsteps 105 and 107.

In step 109, the control mode deciding block 41 compares the predominantwavelength λ₀ stored in the memory unit 19 and the width of the exposurearea 6 inputted from the I/O unit 18; then, it decides whether the tiltof the wafer W in Y-direction (the scanning direction) is controlled ornot based on the result from the focus sensor 7, or not. That is, duringthe synchronous moving, the main control system decides whether the tiltof the wafer W in Y-direction is adjusted by following-up the changebetween the tilt for the wafer W surface in Y-direction obtained fromthe detection result by the focus sensor 7 and that of the target data,or not. Comparing the predominant wavelength λ₀ to the width L₀, and theresult is

λ₀ >L ₀

the control mode deciding block 41 decides that the focusing controlmode to be used in the exposure to be performed from now is the firstmode, and (0, 0) is output as the mode designation signal (MD0, MD1).

Then, in step 113, fundamentally, the main control system 20 movessynchronously both the reticle R and the wafer W, performing thefocusing control in the first mode. After that, the pattern formed onthe reticle R is sequentially transferred onto the respective shot areaon the wafer W. That is, during the scanning exposure, the position ofthe wafer W surface in Z-direction, the tilt of the wafer W inX-direction and in Y-direction are controlled, following-up the changeof the difference between the target value and the measurement valuewhich is obtained from the detection result using the focus sensor 7.According to this, the positioning of the image plane of the projectionoptical system PL and the exposure plane on the wafer W is preciselyperformed in the exposure area 6, and the image of the reticle R isprojected on the wafer W.

In the focusing control by using the first mode, the main control system20 performs the focusing control which tracks the change during thesynchronous moving of the three components of the current value (z,θ_(X), θ_(Y)) from the least-square approximation block 27. However, inthe present embodiment, considering the limit of the driving capacity,i.e., the driving velocity, of the actuators 21A, 22A and 23A, thefocusing control, for example, disclosed in Japan laid-open No. H9-82636and its correspondent, U.S. Pat. No. 5,737,063. The disclosure describedin the above is fully incorporated by reference herein, as far as thelaw of the countries designated in a request or elected in a demand forthe application filed in the country of origin permits them.

This focusing control is explained briefly. During synchronously moving,the focusing control is performed under the condition that the controlmode determining block 28 sets the data (z′, θ_(X)′, θ_(Y)′) as thefollowing-up control target value and sets the value (z, θ_(X), θ_(Y))as the following-up control current value, the main control system 20decides that one of the velocity instruction values Vz₁, Vz₂, and Vz₃,those which are output from the interdependence freeing unit 29, overthe maximum value of the driving velocity for the actuators 21A, 22A,and 23A (the first condition) or not. When the positive decision for thefirst condition is made, the value (1, 1, 1) is output as the controlmode designation signal (SL_(X), SL_(Y), SL_(Z)). Then, the target dataoutputting block 25 outputs the value (z′, θ_(X)′, θ_(Y)′) as the targetfocusing control signal into the subtractors 33A, 33B, and 33C.Alternatively, the multiplexer 32 outputs the three components of thecurrent value (z, θ_(X), θ_(Y)) from the least-square approximationblock 27 into the subtractors 33A, 33B, and 33C. As a result, thefocusing control is performed under the first control condition, i.e.,the change during the synchronous moving of the three components for thecurrent value (z, θ_(X), θ_(Y)) from the least-square approximationblock 27 is tracked.

When the negative decision for the first condition is made, the focusingcontrol is performed under the condition that the control modedetermining block 28 sets the value (z′, θ_(X)′) as the following-upcontrol target value and sets the value (z, θ_(X)) as the following-upcontrol current value. The main control system 20 decides that one ofthe velocity instruction values Vz₁, Vz₂, and Vz₃, those which areoutput from the interdependence freeing unit 29, over the maximum valueof the driving velocity for the actuators 21A, 22A, and 23A (the secondcondition) or not. When the positive decision for the first condition ismade, the value (1, 0, 1) is output as the control mode designationsignal (SL_(X), SL_(Y), SL_(Z)). Then, the target data outputting block25 outputs the value (z′, θ_(X)′, Θ_(Y)′) as the target focusing controlsignal into the subtractors 33A, 33B, and 33C. Alternatively, themultiplexer 32 outputs the three components of the current value (z,θ_(X), Θ_(Y)) from the least-square approximation block 27 into thesubtractors 33A, 33B, and 33C. Wherein, the target data outputting block25 outputs the tilt of the substrate table 10 in Y-direction just priorto switch the control as the target value (Θ_(Y)′). As a result, thefocusing control is performed under the second control condition, i.e.,the change during the synchronous moving of the two components for thecurrent value (z, θ_(X)) from the least-square approximation block 27 istracked.

When the negative decision for the second condition is made, thefocusing control is performed under the condition that the control modedetermining block 28 sets the value (z′, θ_(Y)′) as the following-upcontrol target value and sets the value (z, θ_(Y)) as the following-upcontrol current value (the third control condition). The main controlsystem 20 decides that one of the velocity instruction values Vz₁, Vz₂,and Vz₃, those which are output from the interdependence freeing unit29, over the maximum value of the driving velocity for the actuators21A, 22A, and 23A (the third condition) or not. When the positivedecision for the first condition is made, the value (0, 1, 1) is outputas the control mode designation signal (SL_(X), SL_(Y), SL_(Z)). Then,the target data outputting block 25 outputs the value (z′, Θ_(X)′,θ_(Y)′) as the target focusing control signal into the subtractors 33A,33B, and 33C. Alternatively, the multiplexer 32 outputs the threecomponents of the current value (z, Θ_(X), θ_(Y)) from the least-squareapproximation block 27 into the subtractors 33A, 33B, and 33C. Wherein,the target data outputting block 25 outputs the tilt of the substratetable 10 in Y-direction just prior to switch the control as the targetvalue (Θ_(X)′). As a result, the focusing control is performed under thethird control condition, i.e., the change during the synchronous movingof the two components for the current value (z, θ_(Y)) from theleast-square approximation block 27 is tracked.

When the negative decision for the third condition is made, the controlmode determining block 28 outputs the value (0, 0, 1) as the controlmode designation signal (SL_(X), SL_(Y), SL_(Z)). Then, the target dataoutputting block 25 outputs the value (z′, Θ_(X)′, Θ_(Y)′) as the targetfocusing control signal into the subtractors 33A, 33B, and 33C, and themultiplexer 32 outputs the three components of the current value (z,Θ_(X), Θ_(Y)) from the least-square approximation block 27 into thesubtractors. Wherein, the target data outputting block 25 outputs thetilt of the substrate table 10 in X- and Y-direction just prior toswitch the control as the target value (Θ_(X)′, Θ_(Y)′). As a result,the focusing control is performed under the fourth control condition forholding the posture of the tilt in X- and Y-direction just prior toswitch the control mode, independent of the surface condition of thewafer.

On the contrary, in step 109, when it is decided that

λ₀ <L ₀

the control mode determining block 41 decides that the focusing mode inthe exposure to be performed in future is the second mode, and itoutputs the value (0, 1) as the mode designation signal (MD0, MD1) instep 115.

Then, in step 113, fundamentally, the main control system 20synchronously moves both the reticle R and the wafer W, performing thefocusing control in the second mode. Then, the pattern formed on thereticle R is sequentially transferred onto the respective shot area onthe wafer W. That is, during the scanning exposure, the position of thewafer W surface in Z-direction, the tilt of the wafer W in X-directionare controlled, following-up the change of the difference between thetarget value and the measurement value which is obtained from thedetection result by using the focus sensor 7. Alternatively, the tilt ofthe wafer W in Y-direction is controlled in the predetermined conditionbased on the measured value by using the encoders 21B, 22B, and 23B,without following-up the change between the target value and themeasured value obtained from the focus sensor 7. The tilt of the wafer Win Y-direction might be decided based on the information for the imageplane of the projection optical system PL or that for the surfacecondition (the convex and concave condition) of the shot area on thewafer W obtained in the above-mentioned step 107.

In the focusing control by using the second mode, in the same manner asthe first mode, the focusing control is performed. In the focus control,the change of the two components of the current value (z, θ_(X)) fromthe least-square approximation block 27 during the synchronous moving istracked. However, in the present embodiment, the focusing control isperformed in the same manner as the first mode, considering the limit ofthe driving capacity (driving velocity) for the actuators 21A, 22A and23A.

During synchronously moving, the focusing control is performed under thecondition that the control mode determining block 28 sets the value (z′,θ_(X)′) as the following-up control target value. Then, the main controlsystem 20 decides that one of the velocity instruction values Vz₁, Vz₂,and Vz₃, those which are output from the interdependence freeing unit29, over the maximum value of the driving velocity for the actuators21A, 22A, and 23A (the above-mentioned second condition) or not. Whenthe positive decision for the condition is made, the value (1, 0, 1) isoutput as the control mode designation signal (SL_(X), SL_(Y), SL_(Z)).Consequently, the focusing control is performed in the focusing controlmode.

When the negative decision is made for the second mode, the control modedeciding block 28 outputs the value (0, 0, 1) as the control modedesignation signal (SL_(X), SL_(Y), SL_(Z)). Consequently, the focusingcontrol is performed in the above-mentioned fourth control mode.

As mentioned above, in step 113, when the focusing control mode is thefirst mode or the second mode, the focus control is performed in therange in which the leveling following-up can be practicable in the viewpoint of the performance for the apparatus; thereby the defocus againstthe entire exposure area, and the scanning exposure is performedmaximizing the focal depth in the projection optical system. Then, evenif the leveling following-up is not practicable by the performance ofthe apparatus, the scanning exposure is performed, conducting thefocusing control without serious failure of the control or thegeneration of the fatal defocus amount. The pattern formed on thereticle is thus transferred onto the respective shot areas on the waferW.

Thus, when the transfer of the pattern onto the wafer W is completed instep 113, the procedure goes to step 101. Then, the exposure procedureis performed as the same manner as described above.

As explained hereinbefore, in the present embodiment, the differentfocusing control is performed, depending on the surface condition of theshot area as the divided area which is defined based on that thepredominant wavelength is equal to or wider than the slit width of theexposure area on the wafer W. The predominant wavelength is obtainedfrom the spatial frequency components for which the concave or convexexist inside the shot area, and they are on the synchronously movingdirection. When the predominant wavelength is equal to or wider than theslit width of the exposure area on the wafer W, the main control system20 tracks the synchronously moving of the wafer and performs thefocusing control including the leveling control for the synchronouslymoving direction of the wafer. When the predominant wavelength isshorter, the main control system 20 tracks the synchronously moving ofthe wafer and performs the focusing control except the leveling controlfor the synchronously moving direction of the wafer. Accordingly, thepattern might be transferred without serious deterioration of theimaging performance, performing the focusing control by using the simplestructure that is not premising the high focusing drivingpracticability.

The scanning type exposure apparatus of the present invention detectsthe tilt against the horizontal plane; then, based on the detectionresult, it detects the detection result data obtained from the focusdetecting system while the substrate table is moved in the same manneras the synchronously moving, maintaining the substrate table is almosthorizontal. After that, the predominant wavelength of the shot area isobtained by using the acquisited data. Accordingly, since one sensormight be used as the measurement sensor for the predominant wavelengthand that for the focus position in the synchronously moving, it is notnecessary to correct the difference derived from sensors type and soforth.

In the present embodiment, the predominant wavelength is measured, whenthe main control system 20 decides that it is the first process from thepoint of view of the exposure condition (the process condition)including the pattern formation history on the wafer W, and kinds of thephotoresist agents. When the pattern is transferred by the same process,the predominant wavelength previously measured is used, so that highthrough put might be maintained.

In the present embodiment, when the plural shot areas for exposing underthe same condition are formed on the wafer, the predominant wavelengthis measured for one of the shot area. Therefore, the through put of theexposure procedure is not decreased.

In the scanning type exposure apparatus 100 of the present embodiment,elements shown in FIG. 1 such as the above-mentioned reticle stage 3,the projection optical system PL, the substrate table 10, X-Y stage 11,the focus sensors 7A and 7B, and the main control system for controllingthem are connected electrically, mechanically and optically to assemblethe apparatus 100. After that, the apparatus 100 is totally adjusted(electrical adjustment or inspection of the operation) to produce theexposure apparatus 100. The production of the exposure apparatus 100 ispreferably produced in a clean room in which temperature and cleanlinessof the air are controlled.

An embodiment of a device manufacturing method by using the exposureapparatus and method above will be described.

FIG. 10 is a flow chart showing an example of manufacturing a device (asemiconductor chip such as an IC, or LSI, a liquid crystal panel, a CCD,a thin film magnetic head, a micromachine, or the like). As shown inFIG. 10, in step 201 (design step), function/performance is designed fora device (e.g., circuit design for a semiconductor device) and a patternto implement the function is designed. In step 202 (mask manufacturingstep), a mask on which the designed circuit pattern is formed ismanufactured. In step 203 (wafer manufacturing step), a wafer W ismanufacturing by using a silicon material or the like.

In step 204 (wafer processing step), an actual circuit and the like areformed on the wafer W by lithography or the like using the mask andwafer prepared in steps 201 to 203, as will be described later. In step205 (device assembly step), a device is assembled by using the waferprocessed in step 204. Step 205 includes process such as dicing, bondingand packaging (chip encapsulation).

Finally, in step 206 (inspection step), a test on the operation of thedevice, durability test, and the like are performed. After these steps,the device is completed and shipped out.

FIG. 11 is a flow chart showing a detailed example of step 204 describedabove in manufacturing the semiconductor device. Referring to FIG. 11,in step 211 (oxidation step), the surface of the wafer is oxidized. Instep 212 (CVD step), an insulating film is formed on the wafer surface.In step 213 (electrode formation step), an electrode is formed on thewafer by vapor deposition. In step 214 (ion implantation step), ions areimplanted into the wafer. Steps 211 to 214 described above constitute apre-process for the respective steps in the wafer process and areselectively executed in accordance with the processing required in therespective steps.

When the above pre-process is completed in the respective steps in thewafer process, a post-process is executed as follows. In thispost-process, first, in step 215 (resist formation step), the wafer iscoated with a photosensitive agent. Next as, in step 216, the circuitpattern on the mask is transcribed onto the wafer by the above exposureapparatus and method. Then, in step 217 (developing step), the exposedwafer is developed. In step 218 (etching step), and exposed member on ablock other than a block where the resist is left is removed by etching.Finally, in step 219 (resist removing step), the unnecessary resistafter the etching is removed.

By repeatedly performing these pre-process and post-process, multiplecircuit patterns are formed on the wafer.

As described above, the device on which fine patterns are preciselyformed is manufactured in enhanced productivity.

In the present embodiment, the predominant wavelength is measured, whenthe main control system 20 decides that it is the first process from thepoint of view of the exposure condition (the process condition)including the pattern formation history on the wafer W, and kinds of thephotoresist agents. However, the measurement might be performed in theinitial of the lot on which the pattern is transferred by the sameprocess. Even in this case, the predominant wavelength is measured forsole wafer per lot. Therefore, the high through put might be maintained.

The predominant wavelength might be obtained by calculating in thelithography process for the wafer W that is previously performed,instead of measuring prior to exposure. In this case, since themeasurement time is cut out, the high through put might be maintained.

In the above-mentioned present embodiment, the predominant wavelengthand the slit width of the exposure area on the wafer in thesynchronously moving direction are compared. However, depending on thecharacteristics of the photoresist agent used or the minimum line widthof the pattern to be transferred, the predominant wavelength and theconstant K times value of the above-mentioned slit width might becompared. The constant K is obtained from the experiment, depending onthe characteristics of the photoresist agent used or the minimum linewidth of the pattern to be transferred. In this case, the most suitablefocusing control might be performed.

When the plural chip patterns are formed in the shot area, thepredominant wavelength might be obtained by measuring the spatialfrequency distribution for one chip pattern.

In the present embodiment, when the predominant wavelength is measured,the position of the detection point in Z-direction might be measured,driving the substrate table in the horizontal. However, the positions ofthe detection points in Z-direction on the substrate are measures,moving the substrate table of which tilt to the horizontal plane isfixed. In this case, after the primary component is deleted from theposition data distribution in Z-direction which are acquired in the X-Yplane, the predominant frequency might be obtained in the same manner asthe present embodiment, by processing similarly.

Alternatively, in the measurement of the information for the concave andconvex on the above-mentioned shot area (the spatial frequencydistribution), the throughput is not reduced provided in that the waferW is moved when the alignment mark formed on the wafer W is measured,wherein the alignment mark is formed for obtaining the arrangementinformation of the plural shot areas on the wafer W. The detail for themeasurement of the alignment mark formed on the wafer W is disclosed,for example, in Japan laid-open No. H06-275496 and its correspondingU.S. patent application Ser. No. 183,879 (filing date: Jan. 21, 1994)and its CIP application Ser. No. 569,400 (filing date: Dec. 8, 1995).The disclosure described in the above is fully incorporated by referenceherein, as far as the law of the countries designated in a request orelected in a demand for the application filed in the country of originpermits them.

The information for the convex and concave on the shot area is measuredprior to the above-mentioned scanning exposure and it obtained form thefocus sensor 7. The information can be used described in below.

(1) The information is used as the information for selecting thedetection point to be used in the scanning exposure on the wafer W amongthe plural detection points of the focus sensor. For example, during thescanning exposure on the wafer W, the detection point existing theposition at which a stair having special height difference is formedsuch as the scribe in the shot area. Thereby, the deterioration of thepositioning accuracy between the imaging plane of the projection opticalsystem and the exposure plane of the wafer W is prevented.

(2) The information is used as the information for obtaining the offsetamount (the correction data) to correct the detection result from thefocus sensor 7, in the scanning exposure. For example, in the case thatthe stair part having special height difference is formed such as thescribe is existed in the shot area, the detection result from the focussensor 7 corresponding to the part is corrected by using the offsetamount. Thereby, the imaging plane of the projection optical system andthe exposure plane of the wafer W is precisely positioned although thestair part having special height difference is existed in the shot area.

INDUSTRIAL APPLICABILITY

As described in detail, according to the scanning exposure method of thepresent invention, the focusing control of the substrate is performed byusing the properly adjusted mode; thereby the pattern formed on the maskis transferred on the substrate without serious deterioration of theimaging performance. Alternatively, according to the scanning exposureapparatus of the present invention, the pattern is transferred by usingthe scanning exposure method of the present invention; thereby thepattern formed on the mask is transferred on the substrate withoutserious deterioration of the imaging performance. Accordingly, thescanning exposure method and apparatus are preferably used for the massproduction of the device having the fine patterns.

What is claimed is:
 1. A scanning exposure method for transferring apattern formed on a mask to a divided area on a substrate through aprojection optical system, and synchronously moving said mask and saidsubstrate with respect to an illumination light along a synchronousmoving direction of said substrate, said scanning exposure methodcomprising the steps of: determining a spatial frequency distribution ofthe divided area along said synchronous moving direction of saidsubstrate; deciding to use either a first focusing control modeproviding substrate tilt changing control or a second focusing controlmode maintaining substrate tilt unchanged as a decided mode when saidpattern is transferred onto the divided area depending on the spatialfrequency distribution of the divided area determined by the determiningstep and a width of an illumination area on the substrate in thesynchronous moving direction; and transferring the pattern formed on themask onto the divided area while performing said focusing control in thedecided mode.
 2. The scanning exposure method according to claim 1,wherein said first focusing control mode performs a tilt control tochange substrate tilt in said synchronous moving direction of saidsubstrate, and said second focusing control mode maintains unchangedsubstrate tilt in the synchronous moving direction of the substrate. 3.The scanning exposure method according to claim 2, wherein saidsubstrate is controlled by using said first focusing control in saidfirst mode when a predominant wavelength is equal to or longer than alength corresponding to said width of the illumination area in thesynchronous moving direction of said substrate, the predominantwavelength corresponding to a predominant frequency that has a maximumamplitude in said spatial frequency distribution; and said substrate iscontrolled by using said focusing control in said second mode when apredominant wavelength is shorter than the length corresponding to thewidth of the illumination area in the synchronous moving direction ofsaid substrate.
 4. The scanning exposure method according to claim 3,wherein said length corresponding to said width of the illumination areain the synchronous moving direction of said substrate is a slit width.5. The scanning exposure method according to claim 1, wherein saidspatial frequency distribution of said divided area is determined priorto said transfer of said pattern on said mask onto the divided area. 6.The scanning exposure method according to claim 5, wherein said spatialfrequency distribution of said divided area is determined in every lotof said substrate on which said pattern formed on said mask istransferred prior to said transfer of the pattern.
 7. The scanningexposure method according to claim 5, wherein said spatial frequencydistribution of said divided area is determined in every exposureprocess of said transfer of said pattern formed on said mask onto saidsubstrate prior to said transfer of the pattern.
 8. The scanningexposure method according to claim 5, wherein a plurality of dividedareas are arranged on said substrate; and said spatial frequencydistribution of said divided area is determined by determining thespatial frequency distribution of one of the plurality of divided areas.9. The scanning exposure method according to claim 1, wherein a focusingcontrol is provided that includes a focus position control that controlsa position of said substrate in an optical axis direction of saidprojection optical system; and when it is decided that said focusposition control cannot be performed, following said synchronous moving,a control is performed to maintained said substrate at a position justprior to the decision in an optical axis direction of said projectionoptical system.
 10. The scanning exposure method according to claim 1,wherein a focusing control is provided that includes a tilt control ofsaid substrate in said synchronous moving direction; and when it isdecided that said tilt control cannot be performed, following saidsynchronous moving, a control is performed to maintain a tilt of thesubstrate just prior to the decision in said synchronous movingdirection.
 11. The scanning exposure method according to claim 1,wherein a focusing control is provided that includes a tilt control ofsaid substrate in a direction perpendicular to said synchronous movingdirection and an optical axis direction of said projection opticalsystem; and when it is decided that said tilt control cannot beperformed, following said synchronous moving, a control is performed tomaintain a tilt of the substrate just prior to the decision in saiddirection perpendicular to said synchronous moving direction and saidoptical axis direction of said projection optical system.
 12. Thescanning exposure method according to claim 1, wherein said focusingcontrol mode is decided prior to the step of transferring the patternformed on the mask onto said divided area.
 13. A device manufacturingmethod including a lithographic process, comprising: transferring apredetermined pattern onto a divided area, which is divided by streetlines on a substrate, by using the exposure method according to claim 1.14. A scanning exposure apparatus which is used to transfer a patternformed on a mask onto a divided area on a substrate through a projectionoptical system, and synchronously moving the mask and the substrate withrespect to illumination light along a synchronous moving direction ofsaid substrate, said scanning exposure apparatus comprising: a maskstage which holds the mask; a substrate stage which holds the substrate;a first detecting system which detects a position for at least one ofdetection point in an optical axis direction of said projection opticalsystem, wherein the detection point is in a illumination area on saidsubstrate surface; a first driving system which drives the mask stageand the substrate stage in planes perpendicular to said optical axisdirection of said projection optical system; a second driving systemwhich drives the substrate stage to at least one of the optical axisdirection of the projection detecting system and a tilt direction; amemory unit which stores a data representing a spatial frequencydistribution of said divided area along said synchronous movingdirection of said substrate; and a control system which synchronouslymoves the mask stage and the substrate stage by controlling the firstdriving system, while performing said focusing control by controllingthe second driving system based on a result from the first detectingsystem, wherein a focusing control mode to be used in the transfer of apattern onto said divided area is decided from a plurality of focusingcontrol modes based on the data representing the spatial frequencydistribution of the divided area and a width of an illumination area onthe substrate in the synchronous moving direction.
 15. The scanningexposure apparatus according to claim 14, wherein said plurality offocusing control modes include a first mode in which a tilt control in adirection of said synchronous moving of said substrate is performedfollowing the synchronous moving, and a second mode in which the tiltcontrol in the direction of the synchronous moving of the substrate isnot performed following the synchronous moving.
 16. The scanningexposure apparatus according to claim 15, further comprising a seconddetecting system which detects a tilt of said substrate stage in saidsynchronous moving direction to a virtual plane perpendicular to saidoptical axis direction of said projection optical system and in adirection perpendicular to the said synchronous moving direction; andsaid control system performs said focusing control based on detectionresults from said first and second detecting systems.
 17. The scanningexposure apparatus according to claim 16, wherein said plurality offocusing control modes further include a third mode which maintains saidsurface of said substrate stage in parallel with said virtual planebased on a detection result from said second detecting system, and saidexposure apparatus further comprises a calculating operation unit whichacquires detection result data by using said first detecting systemduring said synchronous moving under the focusing control in said thirdmode, and the exposure apparatus obtains said spatial frequencydistribution of said divided area based on the detection result data.18. The scanning exposure apparatus according to claim 17, wherein saidcalculating operation unit calculates said spatial frequencydistribution formed by concave and convex substrate parts forming arepeating unit area of said pattern to be transferred in said dividedarea along said synchronous moving direction of said substrate, whereinthe concave and convex substrate parts are further formed to be convexand concave in said optical axis direction of said projection opticalsystem; and then the calculating operation unit obtains a predominantwavelength corresponding to a predominant frequency which is maximal inthe spatial frequency distribution to store in said memory unit as saiddata.
 19. The scanning exposure apparatus according to claim 14, whereinsaid control system decides said focusing control mode prior to thetransfer of the pattern onto said divided area.
 20. A devicemanufactured by using said exposure apparatus according to claim
 14. 21.A making method of a scanning exposure apparatus that transfers apattern formed on a mask onto a divided area on a substrate through aprojection optical system, while moving said mask and said substratesynchronously with respect to an illumination light along a synchronousmoving direction of said substrate, said making method comprising:providing a mask stage that holds said mask; providing a substrate stagethat holds the substrate; providing a first detecting system thatdetects a position in an optical axis direction of said projectionoptical system of at least one detection point within an illuminationarea on a surface of said substrate; providing a first driving systemthat drives the mask stage and the substrate stage in a planeperpendicular to said optical axis direction; providing a second drivingsystem that drives the substrate stage in at least one of the opticalaxis direction and a tilt direction; providing a memory unit that storesdata representing a spatial frequency distribution of said divided areaalong said synchronous moving direction of said substrate; and providinga control system that obtains the spatial frequency distribution of thedivided area, decides a focusing control mode to be used whentransferring the pattern onto said divided area as being either a firstfocusing control mode or a second focusing control mode based on theobtained data representing the spatial frequency distribution of thedivided area and a width of an illumination area on the substrate in thesynchronous moving direction, and performs said decided focusing controlmode by controlling the second driving system based on a detectionresult from the first detecting system, while synchronously moving themask stage and the substrate stage by controlling the first drivingsystem, wherein the first focusing control mode performs a tilt controlof the substrate while said pattern is transferred onto the divided areaand the second focusing control mode maintains a tilt of the substratewhile said pattern is transferred onto the divided area.
 22. The makingmethod according to claim 21, further comprising: providing a seconddetecting system that detects a tilt of said substrate stage in saidsynchronous moving direction and in a direction perpendicular to saidsynchronous moving direction, in respect to a virtual planeperpendicular to said optical axis direction of said projection opticalsystem.
 23. The making method according to claim 22, further comprising:providing a calculating operation unit that acquires detection resultdata from said first detecting system during said synchronous movingunder a focusing control that maintains a surface of said substratestage to be substantially parallel to said virtual plane based on adetection result from said second detecting system, and obtains saidspatial frequency distribution of said divided area based on saiddetection result data.
 24. The scanning exposure apparatus according toclaim 21, wherein said control system decides said focusing control modeprior to the transfer of the pattern onto said divided area.